Kicker ZR one channel low

[Perry Babin]

Those numbers don't look familiar. The MJE4343 and MJE4353 may have been used in some of the amps.

Since one failed, you need to replace (at least) all that were in parallel with the one that failed.

The FJA4313 and FJA4213 may be good subs but you'll have to carefully check the bias through the entire thermal operating range to confirm that the bias holds with those transistors.

 

[Perry Babin]

What's the rail voltage?

 

[vincegironda]

my power supply has just failed, Ill have to source another and re-test.

 

[vincegironda]

Did these zr1000's ever use TIP35 and 36c's?

 

[Perry Babin]

I think the rail voltage is just outside the TIP35/36 maximum.

 

[vincegironda]

ok I replaced all the devices in the bad channel,

the amp is now making a loud fizzing - hissing noise.

The noise is coming from the transformer???

 

[Perry Babin]

If you reduce the DC voltage feeding the amp, does the noise change?

If you touch the transformer windings, does the noise change?

 

[vincegironda]

When I power it up with a current limiter the noise reduces a little.

Q122 has blown again and it's gate resistor is dead

 

[Perry Babin]

What did you install in place of the original transistor?

If you touch the transformer windings, does the noise change?

How loud is 'loud'?

 

[vincegironda]

also the amp is tripping my power supply even without remote voltage?

 

[vincegironda]

I manged to find identical transistors to the originals.

 

[Perry Babin]

Are you sure that they weren't counterfeit?

Did any of the power supply FETs fail?

Were the transistors tightly clamped to the heatsink when the output failed?

 

[vincegironda]

the originals were
DE801
MJE4343

DE748
MJE4353

replacements are
DE840
MJE4343

DE841
MJE4353

 

[vincegironda]

The power supply fets appear fine.

 

[Perry Babin]

Fakes can have anything printed on them.

Crack open one of the originals and one of the replacements that failed and compare the appearance of the die. If you squeeze them across their width at a slight open in a vise, they will crack open easily.

 

[Perry Babin]

Did you insulate the screw near the transformer?

 

[vincegironda]

I didn't fit the screw near the transformer.

I broke the devices open and here are the results

 

[vincegironda]

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[vincegironda]

There's definitely a difference.....

Shall pull all the replaced devices and see if it powers up ok?

 

[Perry Babin]

Just pull the shorted ones. Even if they're counterfeit, they should work well enough to test at idle.